Claudio Ranieri praised his players for opening up a four-point gap on Manchester United in the race for second in the Premiership, saying: "Now it is in our hands".

The Blues can afford to lose at Old Trafford next weekend and still claim runners-up spot - and automatic qualification for the Champions League - by beating Leeds at home in the final game of the season.

"The four-point gap is important because everything now is in our own hands," said coach Ranieri.

Chelsea had gone five games without a win and had drawn their previous two home games 0-0, and struggled to break down a resolute Saints defence until the 59th minute, when teenager Martin Cranie headed an own goal.

Paul Sturrock went for broke by going all out for an equaliser, but his team crumbled in the latter stages and Frank Lampard helped himself to a double (76 and 84) before substitute Glen Johnson stroked home the fourth after 86 minutes.

Chelsea must follow it up by overturning a 3-1 deficit on Wednesday when Monaco visit Stamford Bridge in the second leg of their Champions League semi-final clash.

"In our last five matches we didn't lose our focus or our performance but we were unlucky in front of goal, hitting the post and bar and everything else," said Ranieri.

"Today we made a mistake and gave them a chance to score and then we went up the other end and scored an own-goal - that is football, it is crazy, fantastic.

"It was important to score because after that Southampton had to open up, and that gave us more space.

"It was a good performance, four goals, all my players are in good condition and now we are ready to try and take our final chance. We must give our best performance and Monaco must do their worst, but everything is possible."

Saints boss Sturrock criticised his team's passing, but said it had been a difficult week as he has now lost six first-team players through injury.

"It has been a very difficult week for Southampton - it was like Emergency Ward 10 for the players," said Sturrock.

"I felt it was appropriate to look at different systems and players, which is why we played 3-5-2.

"Playing 4-4-2 hasn't worked for us and for 60 minutes we were generally OK. But we were crab-like, moving backward and sideways, and should have been more positive.

"I am very disappointed with our passing, we lost our way. People were slow on the ball and negative.

"But I take the blame because at 1-0 I threw on two wingers and went for it rather than hold on for a 1-0.

"That's what happens when you leave yourself open against quality players."